London Metropolitan University on its entry for Solar Decathlon Europe
By editor | 31 Jan, 2012
The main structural and thermal material of our design will be expanded polystyrene (EPS), which is environmentally friendly, lightweight, highly insulated and acts well in compression. With this in mind, the house design will use an arch or vaulting strategy - treating the EPS like masonry to make the best use of the compressive qualities of the material. As part of the team’s interest in parametric design techniques, we have been able to simulate complex and irregular catenary vault models digitally, which has allowed us to experiment with more intricate structural solutions. The use of EPS material allows our design to be adaptable to any climate.
In order to achieve a solar house that is not only optimised for climate conditions of a particular site, but also has great aesthetic value, we have set out to develop an entirely new lightweight building system, which uses EPS as structural element.
Development of the new foam construction system eliminates the need to divide the building into conventional components such as walls, floors or roof, as well as reducing the number of layers of construction. The entire envelope of the building works as one homogenous system serving as structure and insulation simultaneously, with only the need for a final layer of protection on both the exterior and interior surfaces. We are currently exploring a range of different material finishes to protect the EPS.
As the rules of competition states - the house is required to be completely self-sustaining and must be powered by the sun. Our decision for the PV-T (solar photovoltaic and solar thermal) versus PV on its own was one whereby we had to balance need and production, and is largely designed around the need for basic requirements, such as daily showers and running hot water all year round. During the summer months there is little value in creating surplus thermal energy, however surplus electrical energy can either be stored or sold back to the grid in order to conserve it or recoup costs needed for the winter months when the energy is really needed.
For our design, we will be using an innovative process of cooling the PV down using an air-cooling system, which has massive benefits for the overall electrical output. This is due to the semi conductors (the process PV relies upon) working on a simple principle of the hotter they become, the more resistance they are to electrical production and therefore the less efficient. Our team has been working in collaboration with environmental engineers - BDSP, to develop the system and calculate specifications such as the size of the hollow section behind each PV cell in order to maintain a maximum temperature of 45°C. The house will also contain an arrangement of PV-T, in order to maximise its winter morning electrical output.
The external surface of the house will also contain a green wall in a rooftop location, which will improve the micro-climate around the house and reduce water run-off. As the house is designed for urban development, it is important that attention is paid to houses biodiversity qualities. Further development is being made in this area and a planting strategy will be researched.
If you think your organisation can contribute in any way to the development of this project, please get in touch at firstname.lastname@example.org and we will be happy to discuss a number of options.
Don’t forget to keep up-to-date with the latest developments by following @sunbloc2012.
This article appeared in the January/February 2012 issue of Greenbuild. For a free subscription, click here.
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